Here is the full list of all 43 Over 9000 Zombies! achievements.
The army of the undead will march at daybreak!
No 8th symphony for zombie Sibelius!
Voted the greatest zombie of all time!
Construct 100 automated turrets.
Collect 100 Power Ups!
Kill over 1000 crabs!
Kill over 1000 zombie eyes!
Kill over 1000 zombie crows!
Get 15,000 damage per second!
Zombie Napoleon meets his zombie Waterloo!
Kill over 1000 zombie dogs!
Participate in a multiplayer game.
Get 5,000 damage per second!
Get 10 kills per second!
Kill 90,000+ Zombies!
The zombie world is independent of our will.
Abused patience turns to fury!
Health is the greatest gift, a close second is BRAINS!
Terror possessed me then!
If only he had the body of a horse...
A jail is an isolated system.
Vote for Zombie Thomas Jefferson, or don't.
Blood and Flesh can be trusted.
Quoth the Raven "Nevermore."
Decreased Zombotropy.
Don't call me slow!
Your world didn't end!
You didn't donate your organs...
It didn't taste like chocolate ice cream either...
Not a wimp.
Lots of progress!
You watched the world burn, and survived. It was kind of cool.
Green IS good.
Kill 9,000+ Zombies!
You won that race.
Making some progress...
Construct a turret from scrap metal!
Kill 1000+ Zombies!
The first day is always the hardest, except in this case, it's the easiest.
Kill 900,000+ Zombies!
Construct 1000 Turrets from random scraps of metal!
Get 30 kills per second!
Derail the Waltz of the Undead!